System For Position Detection

ABSTRACT

The invention relates to a position determination and regulation system for working devices arranged on the working arms of mobile machine-tools. Said system comprises at least one sensor and an emission/reception unit. The determination and transmission of position co-ordinates (x, y) and/or an incline (φ) of the working device between the at least one sensor and the emission/reception unit are carried out in a contact-free manner.

The invention relates to a system for position detection and control of operating arms of mobile machines according to the preamble of claim 1.

In the case of position-controlled operating arms of mobile machines, the position of the operating mechanisms is usually detected indirectly by length sensors in cylinders of the hydraulic system or by angle sensors. An example of position detection by angle sensors is known from DE 100 00 771 A1. The publication describes a device for position control for operating mechanisms of mobile machines which comprises a measuring device for measuring an angle which is formed between a plane determined by the position of the operating mechanism and the direction of the gravitational force, an angle transmitter for prescribing an angle which is formed between a plane determined by the position of the operating mechanism and the direction of the gravitational force, and a control device for controlling the angle between the plane of the operating mechanism and the direction of the gravitational force so that the measured angle comes to correspond with the prescribed angle.

In particular, the merely very limited possibility for detecting interferences and inaccuracies is disadvantageous in systems of this type, so that the possibility of adjustment to maximum power is likewise restricted.

It is known furthermore to detect the position of mobile machines on the ground by means of positioning systems (e.g. GPS, global positioning system). An operating device equipped with a detection system of this type emerges for example from WO 95/30799.

In particular the cost factor and the precision are thereby disadvantageous in position detection systems of this type. A transmitter/receiver which is suitable for application for this purpose is cost-intensive and high-maintenance.

An object of the present invention hence resides in providing a system for position detection and control for operating arms of mobile machines, which enables simple, economical and accurate position measurement and repositioning of the operating mechanism provided on the operating arm.

The object is achieved by the characterising features of claim 1.

The transmission or determination of position coordinates and/or inclination of the operating mechanism between at least one sensor and one transmitting/receiving unit is advantageously effected without contact by transmitting signals by means of electromagnetic waves.

The sub-claims include advantageous developments of the invention.

Advantageous embodiments of the invention are represented schematically subsequently with reference to the Figures. There are shown in the drawings:

FIG. 1 a schematic representation of a first embodiment of the system according to the invention for position detection and position control of movable operating arms of mobile machines; and

FIG. 2 a schematic representation of a second embodiment of the system according to the invention.

FIG. 1 shows, in a greatly schematic representation, an embodiment of a system which is configured according to the invention for position detection and position control for an operating arm 2 of a mobile machine 1. The machine 1 in the presently described embodiment is thereby an earth-moving device, such as e.g. a digger, having an operating mechanism 3 disposed on the operating arm 2, a digger bucket in the embodiment. However the invention is not restricted thereto but can be applied also for other applications, such as e.g. for cranes, concrete pumps, telehandlers etc.

The position detection of the operating mechanism 3 is effected according to the invention via contact-free sensors 4, preferably based on radio signals with microwave technology or high-frequency electromagnetic waves. The sensors 4 are positioned on the operating arm 2 or on the operating mechanism 3 wherever the position is intended to be detected. In the first embodiment represented in FIG. 1, one of the sensors 4 is disposed in the operating mechanism 3 disposed on the operating arm 2 and a further sensor 4 is disposed in a hydraulics unit 6 of the operating arm 2.

Active and particularly advantageously passive sensors 4 are suitable as sensors 4. Active sensors 4 are thereby supplied for example by a battery, as a result of which several years of freedom from maintenance can be achieved. If necessary, environmental energy can be used for charging. When using passive sensors 4, a transmitting/receiving unit 5 is installed on the mobile machine 1. The signals transmitted by the transmitting/receiving unit 5 are converted in the passive sensor 4 and returned in coded form. The measuring accuracy of systems of this type is, in the case of current microwave technology, a few centimetres, the range in the sense of the application is unlimited. Transmission of signals from other types of sensors 4, for example from pressure sensors, can be implemented with comparable technology.

The position and orientation of the operating mechanism 3 is determined by the cooperation of the sensors 4 and of the transmitting/receiving unit 5. The first sensor 4 disposed on the operating mechanism 3 thereby picks up the position and orientation for example in the form of variables x and y for the position determination and φ for the inclination determination of the operating mechanism 3 and conveys the signals without contact to the transmitting/receiving unit 5. The absolute position and orientation of the reference system, i.e. of the machine 1, can be determined by GPS (global positioning system), inclination or acceleration sensors. Equally, for example pressure signals of the hydraulics unit 6 or other physical variables, such as e.g. speed or acceleration of the operating mechanism 3 and the temperature of the fluid and the volume flow through the system can be conveyed further without contact. In FIG. 1, a pressure sensor 4 is illustrated by way of example in the hydraulics unit 6.

The transmitting/receiving unit 5 is in communication in the machine 1 with further components, such as e.g. a control unit 9 and a control lever 10 for operating by the machine driver of the machine 1. Movements carried out by the machine driver via the control lever 10 are converted by the control unit 9 into corresponding signals and movements of the operating mechanism 3.

The signals for determining the position and orientation of the operating mechanism 3 are thereby determined by at least one sensor 4 in the operating mechanism 3 on the basis of running time measurements between the individual parts of the device. The signals of the further physical variables, such as e.g. pressure, speed, acceleration, temperature and volume flow, can be transmitted directly to the transmitting/receiving unit 5.

The communication of the sensors 4 with the transmitting/receiving unit 5 can however be made difficult or impossible by obstacles, such as for example a wall 7, illustrated in FIG. 2.

In order to counteract this, the system according to FIG. 1, as represented in a second embodiment in FIG. 2, can be provided advantageously with an amplifier unit 8 which assists communication between the sensors 4 and the actual transmitting/receiving unit 5 on the machine 1. In order to determine the position and orientation of the operating mechanism 3, the amplifier unit 8 is disposed such that it has a direct visual connection to both units. As represented in the embodiment according to FIG. 2, it can be disposed on the operating arm 2 of the machine 1 or also at a suitable position outside the machine 1. The amplifier unit 8 can thereby be designed such that, on the basis of the same technology as the main system, it picks up in addition separate data, such as for example position information and transmits it to the transmitting/receiving unit 5. The data can be used for control or for operator assistance.

The invention is not restricted to the illustrated embodiments but can be applied with any machine 1 using different sensors 4 for different operating mechanisms 3. The features of the invention can thereby be combined in any manner. 

1. System for detection and control of operating mechanisms (3) disposed on operating arms (2) of mobile machines (1), comprising at least one sensor (4) and a transmitting/receiving unit (5), characterised in that the transmission and detection of position coordinates (x, y) and/or of an inclination (φ) of the operating mechanism (3) between the at least one sensor (4) and the transmitting/receiving unit (5) is effected without contact.
 2. System according to claim 1, characterised in that the at least one sensor (4) is configured as an active sensor (4).
 3. System according to claim 1, characterised in that the at least one sensor (4) is configured as a passive sensor (4).
 4. System according to one of the claims 1 to 3, characterised in that the at least one sensor (4) is disposed in the operating mechanism (3).
 5. System according to claim 4, characterised in that signals emitted via a control lever (10) of the machine (1) can be transmitted by the transmitting/receiving unit (5) and the at least one sensor (4) to the operating mechanism (3).
 6. System according to one of the claims 1 to 5, characterised in that at least one further sensor (4) is disposed in a hydraulics unit (6) of the operating arm (2).
 7. System according to claim 6, characterised in that the sensor (4) disposed in the hydraulics unit (6) transmits a pressure signal (p).
 8. System according to one of the claims 1 to 7, characterised in that the system has an amplifier unit (8).
 9. System according to claim 8, characterised in that the amplifier unit (8) is configured in the form of at least one transmitting/receiving unit (5).
 10. System according to claim 8 or 9, characterised in that the amplifier unit (8) is disposed on the operating arm (2) of the machine (1).
 11. System according to claim 8 or 9, characterised in that the amplifier unit (8) is disposed separately from the machine (1).
 12. System according to one of the claims 8 to 11, characterised in that the amplifier unit (8) is in direct visual contact with the at least one sensor (4) and the transmitting/receiving unit (5).
 13. System according to one of the claims 1 to 12, characterised in that the transmission of the signals is effected on the basis of a radio signal, in particular on the basis of microwaves.
 14. System according to one of the claims 1 to 13, characterised in that in addition physical variables (p) can be transmitted via the system to the transmitting/receiving unit (5). 